Differential expression of house-keeping genes of Aspergillus nidulans during sexual development

The rpl3 gene and the rpl37 gene for Aspergillus nidulans ribosomal protein L3 (RPL3) and RPL37, which were identified as located on chromosome I and chromosome III, respectively, were isolated from chromosome-specific cosmid libraries. The nucleotide sequences of both of the rpl3 gene and the rpl37 gene identified the ORFs of 392 amino acids and 92 amino acids, respectively. Both of the two genes were present in a single copy. The expression of both genes together with two other house-keeping genes, the rps16 gene for RPS16 and the gene for gamma-actin, was analyzed during sexual development. All four genes showed nearly identical expression patterns in that each gene expression reached its maximum after 2 h, decreased thereafter, and increased again after 30-40 h of induction of sexual development.